Japanese Patent No. 2552427 (Japanese Patent Application Laid-Open Publication No. H07-185131) discloses a game apparatus at which a player operates a character so as to have the character play boxing. In the game apparatus, an image of a player, to which a marker (LED (light-emitting diode)) has been attached, is taken by a fixed camera (CCD (charge-coupled device)), and the position of the marker is detected from the taken image. The movement of a player character is then controlled as if a portion corresponding to a portion (a player's portion) at which the marker is attached is, in an imaginary space, at a position within the imaginary space corresponding to the detected position, with the position of the marker having been detected.
In the above game apparatus, the movement of a player character can be adjusted to match the player's motion to some extent if the detecting cycle of a position is shortened and the accuracy in detecting positions is enhanced. However, it is a position, not a player's motion, that is detected by the above game apparatus, and it will not be possible to sufficiently reduce the possibility of not performing a process corresponding to a player's motion even if the detecting cycle of a position is shortened to the extent possible or the accuracy in detecting positions is enhanced to the extent possible. For example, the motion of a character when a player performs a punching motion sometimes does not appear to be a punching motion. In this case, a player will have a feeling of strangeness of the motion of the character. This problem may occur not only at a game apparatus but also at a freely selected apparatus at which, in a case in which an operator performs a predetermined motion, a process corresponding to the motion should be performed.
Accordingly, in a freely-selected apparatus at which, in a case in which an operator performs a predetermined motion, a process corresponding to the motion should be performed, the present invention sufficiently reduces the possibility of a process corresponding to a motion not being performed even though the operator performed the motion, by determining whether the operator has performed the motion.